Many cancer treatments work by damaging the DNA of cancer cells. However, some tumors survive because they have powerful DNA repair systems that allow them to fix the damage and continue growing. This ability often makes cancers resistant to drugs over time.

A team of researchers has now found a way to disrupt those repair systems. Their study focused on a small molecule called UNI418, which reduces the levels of key proteins that cancer cells need to repair damaged DNA.

Without these proteins, cancer cells struggle to recover from DNA damage, making them more vulnerable to treatment.

The researchers found that UNI418 activates a natural process inside cells that removes specific proteins. As a result, important DNA repair proteins are broken down, effectively shutting down one of the cancer cell's main defense mechanisms.

The discovery could be particularly important for improving the effectiveness of PARP inhibitors, a group of cancer drugs used to treat certain tumors. While these drugs can be highly effective, many cancers eventually become resistant to them.

In laboratory tests, UNI418 made cancer cells far more sensitive to PARP inhibitors. The effect was especially noticeable in cancer cells that had already stopped responding to treatment. In those cases, the molecule helped restore the drugs' effectiveness.

The approach also showed encouraging results in animal studies, where tumor growth slowed significantly when UNI418 was combined with the PARP inhibitor Olaparib.

Researchers say the findings reveal a new way of fighting cancer—not by altering genes, but by dismantling the repair systems that help tumors survive treatment. While more research is needed before the approach can be tested in patients, the study offers fresh hope for developing treatments against drug-resistant cancers.